The resonance effect induced by the variable compliance vibration for an elastic rotor supported by roller bearings

Abstract

Owing to orbital rotation of the rolling element complement and depending on the state of bearing preload, the dynamic stiffness of bearing alters. This causes a vibration at a frequency equivalent to the number of rolling elements multiplied by the cage speed named as variable compliance vibration, which could be much larger than the system nature frequencies. In this paper, the resonance effect induced by the variable compliance vibration of an elastic rotor is discussed. Simplified bearing and the Timoshenko elements are employed to model the system, and then cascade plots and frequency spectrums are mainly obtained as results with two types of resonance in low-speed region. Firstly, resonance of variable compliance frequency would occur while the variable compliance frequency meets the system nature frequencies, which are different in the horizontal and vertical directions. Secondly, resonance of sub-harmonic frequencies which are close to the system nature frequencies would occur while the variable compliance frequency meets the sum of system nature frequencies.